Peripheral Hemolysis in Relation to Iron Rim Presence and Brain Volume in Multiple Sclerosis.

BACKGROUND

Iron rim lesions (IRLs) represent chronic lesion activity and are associated with a more severe disease course in multiple sclerosis (MS). How the iron rims around the lesions arise in patients with MS (pwMS), and whether peripheral hemolysis may be a source of iron in rim associated macrophages, is unclear.

OBJECTIVE

To determine a potential correlation between peripheral hemolysis parameters and IRL presence in pwMS.

METHODS

This retrospective study included pwMS, who underwent a 3T brain MRI between 2015 and 2020 and had a blood sample drawn at ± 2 weeks. Patients with vertigo served as a control group.

RESULTS

We analyzed 75 pwMS (mean age 37.0 years [SD 9.0], 53.3% female) and 43 controls (mean age 38.3 years [SD 9.8], 51.2% female). Median number of IRLs was 1 (IQR 4), 28 (37.3%) pwMS had no IRLs. IRL patients showed significantly higher Expanded Disability Status Scale (EDSS) compared to non-IRL patients (median EDSS 2.3 [IQR 2.9] vs. 1.3 [IQR 2.9], = 0.017). Number of IRLs correlated significantly with disease duration ( = 0.239, = 0.039), EDSS ( = 0.387, < 0.001) and Multiple Sclerosis Severity Scale (MSSS) ( = 0.289, = 0.014). There was no significant difference in hemolysis parameters between non-IRL, IRL patients (regardless of gender and/or disease type) and controls, nor between hemolysis parameters and the number of IRLs. Total brain volume was associated with fibrinogen (= -0.34, 95% CI -1.32 to -0.145, = 0.016), and absolute cortical and total gray matter volumes were associated with hemoglobin ( = 0.34, 95% CI 3.39-24.68, = 0.011; = 0.33, 95% CI 3.29-28.95, = 0.015; respectively).

CONCLUSION

Our data do not suggest an association between hemolysis parameters and IRL presence despite a significant association between these parameters and markers for neurodegeneration.